1. Field of the Invention
The present invention relates to a method and apparatus for reducing current consumption by a memory refresh operation. More particularly, the present invention relates to a method for controlling a refresh operation by classifying loaded data into data based on its retention characteristic (or “on its need for retention”).
2. Description of the Related Art
Dynamic Random Access Memory (DRAM) stores data by storing charge in a cell capacitor. To retain the data by the DRAM, the charge stored in the cell capacitor is continuously maintained. As time goes by, the charge stored in the cell capacitor is reduced due to leakage of current. If the stored charge is reduced, a voltage across the cell capacitor is reduced to less than a predefined level. Accordingly, data loss may occur. Therefore, the DRAM needs a refresh operation for a cell capacitor in which a charge is stored at predefined times to retain data.
The refresh operation is periodically performed. Considerable current consumption is needed for the periodic refresh operation. Such excessive consumption of electric current reduces the useful lifetime of a battery, which in turn causes inconvenience for users of devices including DRAM. Therefore, a need exists for a method and an apparatus which reduce current consumed by a DRAM refresh operation.
The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present invention.